As illustrated in Fig. 1, scientist used gold nanocages (AuNCs) as the carrier of small molecule drug doxorubicin due to its large specific surface, high drug loading efficiency, and good photothermal effect. After loading doxorubicin into the gold nanocage, four pre-designed microRNA strands were connected to the surface of the gold nanocage respectively, forming a special DNA nanobark structure.
When gold nanocages loaded with small molecule drugs are internalized into tumor cells, miRNA-21 and miRNA-155 preferentially pair with the S1 RNA strand and release the S3 strand. At this point, the presence of Mg2+ in the cell will activate the activity of Mg2+ -dependent DNAzyme and cut the S4 chain, thereby opening the DNA lock and releasing small molecule drugs to kill tumor cells. In addition, due to the excellent photothermal properties of gold nanocages, the use of auxiliary photothermal therapy can better kill tumor cells.
Fig.1 Principle of the amplified drug delivery system. (Ye, 2022)
After completing the proof-of-concept of the drug delivery model, the researchers first targeted MCF and 4T1 cells to investigate the anticancer effect of the drug delivery system in vitro. The results showed that the biocompatibility of AuNCs was excellent in the absence of near-infrared light (NIR), which lead to the activity of the two cells was not affected by the addition of AuNCs. The Dox in this system could be effectively released in cancer cells. In addition, they also explored the effect of photothermal therapy and chemo-photothermal therapy by exposing the above mixed system to 10 min irradiation time with NIR light.
The above experimental results prove that this new drug delivery system can achieve targeted drug delivery to tumors, and the addition of photothermal therapy can further improve the therapeutic effect of tumors.
Reference
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